This invention relates to a photographic light-sensitive material and more particularly it relates to a photographic light-sensitive material improved in antistatic properties without giving adverse effect on the photographic characteristics.
In general, photographic light-sensitive materials comprise a support having electrical insulation properties and a photographic light-sensitive layer and so they are apt to undergo friction or separation due to contact with similar or different materials during preparation or use of them to cause formation of static charges resulting in adsorption of foreign matters or dusts. The static charges may further cause various troubles such as repellency, desensitization, peeling, etc. Besides, when the static accumulated is discharged, there often occurs the significant defect of photographic characteristics called static markings on the light-sensitive emulsion layer. An attempt has been made to overcome this problem by providing antistatic back coating layer which can dissipate the static charges onto the electrically insulating surface.
Thus, various materials have been employed in order to prevent static build-up of photographic light-sensitive materials. These materials include ionic conductive materials or hygroscopic materials. A generally employed method has been to impart conductivity to lightsensitive materials, thereby to make rapid dissipation of the electric charges prior to discharge caused by accumulation of charges. In order to impart antistatic properties directly to a support of photographic light-sensitive materials, it has been known to directly incorporate these materials into a polymeric material which constitutes the support or to coat them on the surface of the support. For the latter method, the materials are coated as a mixture with polymeric materials such as gelatin, polyvinyl alcohol, cellulose acetates, etc. in order to improve retention of especially antistatic agents The antistatic agent may be added to a light-sensitive emulsion layer provided on a support, but may also be added to other non-light-sensitive auxiliary layers (for example, back coating layer, antihalation layer, intermediate layer, protective layer, etc.)
Most of the conventional antistatic agents do not have satisfactory effects in light-sensitive materials having an emulsion layer of high sensitivity, especially under low humidity or they are deteriorated in their characteristics with time or cause troubles in adhesion under high temperature and high humidity conditions. Furthermore, antistatic agent in non-light-sensitive auxiliary layers sometimes acts on the contiguous light-sensitive emulsion layer especially under high temperature and high humidity to cause deterioration of photographic characteristics such as increase of fog density and obstruction of development.